A wrench of this kind is known from U.S. Pat. No. 3,604,106. In this, there is disclosed an open box-end wrench similar to DIN 898 having a radial opening for insertion of a shank of a bolt, the hexagonal head of which can be turned by a polygonal point configuration. In the corner regions of the polygonal point configuration, there are stop balls, which engage against an end face portion of the hexagonal cross-section of the bolt head for axial retention in the inward opening.
In U.S. Pat. No. 5,782,148, there is described a socket for fitting onto a bolt head that has the shape of a hexagonal profile. The internal cross-section of this tool, which is also called a socket, has two cross-sectional planes, one above the other in the axial direction. The cross-sectional plane adjacent to the opening has a twelve-fold symmetry and twelve angular notches in total, which correspond to the total of six hexagon corners of the hexagonal cross-section of the bolt head. When a bolt head is inserted into the wrench opening, every second angular notch is then occupied by a hexagon corner. The second cross-sectional plane, which is at a distance from the opening, has only a six-fold symmetry, specifically the internal shape of a hexagon. This hexagonal internal cross-section is formed by elongated angular notches. Between these elongated angular notches, there are as a result shorter angular notches, which are closed at the end. These portions of material, which close off the angular notches, provide three flanks that act as stops for end face portions of the hexagon cross-section, when its hexagon corners are inserted into the short angular notches. The hexagonal cross-section of the bolt head can therefore be inserted into the opening of the socket in two angular positions which differ by 30°. It extends therefore more deeply or less deeply into the socket.
A similar jaw arrangement, but on a box-end wrench, is described by EP 1 003 627 B1, in which, depending on the angular position of the hexagon cross-section, the bolt head lies either in a stop position or can be inserted through the jaw opening.
U.S. Pat. No. 7,340,983 B2 describes a ratchet wrench having an internal polygonal cross-section, which consists of two different cross-section portions that lie side by side in the axial direction. A first cross-section portion has a twelve-fold symmetry. A second portion has a six-fold symmetry, so that a nut abuts against stops in a first angular position, and in a second angular position, the nut can be inserted through the opening of the wrench.
It is an object of the invention to broaden the field of use of a wrench of the generic kind.